1. Field of the Invention
The present invention relates to a separating method and arrangement for cutting cold pilgered tubes to length during rolling on a cold pilger rolling mill with a reciprocating rolling stand and intermittent advance and/or intermittent rotation of the tube in the region of one or both dead centers of the rolling stand.
2. Description of the Related Art
In contrast to tubes manufactured by means of other rolling methods, the cutting of tubes rolled in cold pilger rolling mills poses problems because, due to the typical pilger method, the tube is rolled with cyclically different speeds and, in addition, is turned or rotated intermittently. DE 31 05 780 A1 proposes the use of revolving knife cutting arrangements if it is the goal of the operator of a rolling mill to cut the pilgered tubes behind the cold pilger rolling mill in order to avoid large exit lengths, i.e., to avoid large machinery installations and factory space. However, these cutting arrangements have the disadvantage that the revolving knives produce burrs at the ends of the tubes which prevent the insertion of the plug during subsequent drawing of the tubes. This problem is solved by once again cutting off short end portions of the tubes which had been cut previously during the rolling procedure. The additional cuts are usually performed by means of cutting disks, saws or the like. This cutting procedure also produces a slight burr, however, this burr can be easily removed by brushing.
It would also theoretically be conceivable to use cutting disks or saws for cutting the tubes during the rolling procedure. However, cutting disks or saws cannot be used because the intermittent rotation of the tube temporarily and non-uniformly causes too much material to be supplied to the cutting tool, so that the cutting tools are overloaded and damaged or destroyed as a result.